hi,
Even I have not worked on Report Painter, but all I could understand is that its a way of reporting in FI-CO. Anyways, in your case probably the link would be in the the 'ZPMS001' in EXTDREOPRT field in the default values. This could either be a program, include or a variant. since this is custom you will have to try and find out existance of ZPMS001 (i think it should be a variant: tabble VARI)
Below is a link for your help:
http://scn.sap.com/thread/936447
Please let me know results of your RnD.
Regards,
DN.